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drm/i915/dp: Ensure the HW is powered during HW state readout 

The assumption when adding the intel_display_power_is_enabled() checks
was that if it returns success the power can't be turned off afterwards
during the HW access, which is guaranteed by modeset locks. This isn't
always true, so make sure we hold a dedicated reference for the time of
the access.

Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1455296121-4742-10-git-send-email-imre.deak@intel.com
(cherry picked from commit 6fa9a5ecf7)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
This commit is contained in:
Imre Deak 2016-02-12 18:55:18 +02:00 committed by Jani Nikula
parent 02f9f5e62a
commit b81b801f86
1 changed files with 14 additions and 4 deletions
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18
drivers/gpu/drm/i915/intel_dp.c
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@ -2362,15 +2362,18 @@ static bool intel_dp_get_hw_state(struct intel_encoder *encoder,
struct drm_i915_private *dev_priv = dev->dev_private;
enum intel_display_power_domain power_domain;
u32 tmp;
bool ret;
power_domain = intel_display_port_power_domain(encoder);
if (!intel_display_power_is_enabled(dev_priv, power_domain))
if (!intel_display_power_get_if_enabled(dev_priv, power_domain))
return false;
ret = false;
tmp = I915_READ(intel_dp->output_reg);
if (!(tmp & DP_PORT_EN))
return false;
goto out;
if (IS_GEN7(dev) && port == PORT_A) {
*pipe = PORT_TO_PIPE_CPT(tmp);
@ -2381,7 +2384,9 @@ static bool intel_dp_get_hw_state(struct intel_encoder *encoder,
u32 trans_dp = I915_READ(TRANS_DP_CTL(p));
if (TRANS_DP_PIPE_TO_PORT(trans_dp) == port) {
*pipe = p;
return true;
ret = true;
goto out;
}
}
@ -2393,7 +2398,12 @@ static bool intel_dp_get_hw_state(struct intel_encoder *encoder,
*pipe = PORT_TO_PIPE(tmp);
}
return true;
ret = true;
out:
intel_display_power_put(dev_priv, power_domain);
return ret;
}
static void intel_dp_get_config(struct intel_encoder *encoder,